Search found 389 matches

by JohnM
Mon Sep 14, 2020 5:37 pm
Forum: General chat
Topic: Discovery of Phosphine in the Atmosphere of Venus
Replies: 0
Views: 19

Discovery of Phosphine in the Atmosphere of Venus

So we now know about the great announcement. Astronomers have discovered Phosphine in the atmosphere of Venus. However there are a lot of uncertainties as the biological process that generates Phosphine in not understood on Earth. In the case of Venus the 'life' would have to survive the extreme aci...
by JohnM
Fri Sep 11, 2020 8:09 pm
Forum: Space exploration
Topic: SPA Space Suit on Facebook
Replies: 1
Views: 25

Re: SPA Space Suit on Facebook

Have a look at this paper as well https://www.aerosociety.com/media/4847/ ... othing.pdf which covers some of the UK developments in high altitude RAF suits.
by JohnM
Fri Sep 11, 2020 8:01 pm
Forum: Space exploration
Topic: SPA Space Suit on Facebook
Replies: 1
Views: 25

SPA Space Suit on Facebook

Hello eveyone To support tonight's broadcast there is a PHD thesis on the history of space suits at http://tuprints.ulb.tu-darmstadt.de/2103/1/lunen_diss.pdf One thing to remember the first 'space suits' were designed for pilots in very high altitude aircraft and balloons. Pilots in U2 / SR71 and si...
by JohnM
Thu Sep 10, 2020 3:28 pm
Forum: Observing
Topic: Comet 2020 P-4C SOHO bright
Replies: 5
Views: 61

Re: Comet 2020 P-4C SOHO bright

The two comets have disappeared from CalSky now - I suspect they were an error in the input data
by JohnM
Thu Sep 10, 2020 6:30 am
Forum: Observing
Topic: Comet 2020 P-4C SOHO bright
Replies: 5
Views: 61

Re: Comet 2020 P-4C SOHO bright

Looks like an error in the algorithm - giving the comet a magnitude that is not justified by its performance.

It was clear here this morning but I did not get up to look in the vital hour between the comet rising and the sky becoming bright.
by JohnM
Wed Sep 09, 2020 8:55 pm
Forum: Observing
Topic: Comet 2020 P-4C SOHO bright
Replies: 5
Views: 61

Re: Comet 2020 P-4C SOHO bright

Are you sure that is correct ? Cartes du Ciel has 2020 P4-C SOHO at mag 13.5 which means it would have to increase by almost 14 magnitudes to be that bright. I can't see any other web references to the outburst. This is supported by the site http://astro.vanbuitenen.nl/comet/2020PC4 which shows 0.9 ...
by JohnM
Tue Sep 01, 2020 3:40 pm
Forum: Observing
Topic: Betelgeuse fades again
Replies: 11
Views: 96

Re: Betelgeuse fades again: new ATEL Publication

Hot news - or should that be cool news about Betelgeuse There has been another Astronomers Telegram which is proposing that the second dimming is due to another dust cloud see http://www.astronomerstelegram.org/?read=13982 for details however from other information I thought the dust cloud theory ha...
by JohnM
Tue Sep 01, 2020 1:26 pm
Forum: Observing
Topic: Betelgeuse fades again
Replies: 11
Views: 96

Re: Betelgeuse fades again

Eva, There is a discussion about the reasons for Betelgeuse fading in the talk by Dr Mark Kidger to the BAA, this is available on You Tube at https://www.youtube.com/watch?v=yYK-28E8c0A . When watching bear in mind this was before the latest fade and there have been a couple of other relevant papers...
by JohnM
Mon Aug 31, 2020 8:29 pm
Forum: Observing
Topic: Betelgeuse fades again
Replies: 11
Views: 96

Re: Betelgeuse fades again

From what has been mentioned in various places the best way of measuring the brightness of Betelgeuse is to use a photometer but the number of people still using these is quite small though there are several in the AAVSO. One reason I think is that the photometers that are still made are quite expen...
by JohnM
Mon Aug 24, 2020 6:10 pm
Forum: Observing
Topic: Betelgeuse
Replies: 30
Views: 4944

Re: Betelgeuse

Following solar conjunction the latest evidence is showing Betelgeuse is fading again. I have created a new thread for the post June dimming. Also I note the comments about the Purkinje effect or shift above - more at https://en.wikipedia.org/wiki/Purkinje_effect though there is a lot more in some o...
by JohnM
Mon Aug 24, 2020 10:14 am
Forum: Observing
Topic: Here today - gone tommorow ?
Replies: 0
Views: 39

Here today - gone tommorow ?

At the end of June there was an announcement by ESO that a massive star had disappeared without following the normal route of exploding as a supernova (SN). Two explanations have been proposed one that the star suddenly became less bright perhaps at the end stage of being a Luminous Blue Variable or...
by JohnM
Sun Aug 23, 2020 7:32 pm
Forum: Observing
Topic: Betelgeuse fades again
Replies: 11
Views: 96

Re: Betelgeuse fades again

Brian et al, There is a review of the possible causes for Betelgeuse dimming (and if it will become a SN) in the talk to the BAA by Dr Mark Kidger of ESA. See https://www.youtube.com/watch?v=yYK-28E8c0A . This rejects most if not all the theories for the dimming event. It also casts doubts on some o...
by JohnM
Sun Aug 23, 2020 2:07 pm
Forum: Observing
Topic: Betelgeuse fades again
Replies: 11
Views: 96

Re: Betelgeuse fades again

Some more information on the new fade: AAVSO light curve https://www.aavso.org/lcg/plot?auid=000-BBK-383&starname=BETELGEUSE&lastdays=200&start=&stop=2459085.07778&obscode=&obscode_symbol=2&obstotals=yes&calendar=calendar&forcetics=&pointsize=1&width=800&height=450&mag1=&mag2=&mean=&vmean=&grid=on&v...
by JohnM
Sun Aug 23, 2020 1:35 pm
Forum: Observing
Topic: Betelgeuse fades again
Replies: 11
Views: 96

Betelgeuse fades again

Betelgeuse had returned to almost normal brightness when is disappeared from view due to solar conjunction. It was predicted that when it returned to view in late July / Early August that it would still be at normal brightness. During solar conjunction astronomers used the STEREO solar observation s...
by JohnM
Wed Jun 17, 2020 11:01 am
Forum: Observing
Topic: Noctilucent Cloud - Morning of 17th June 2020
Replies: 2
Views: 406

Noctilucent Cloud - Morning of 17th June 2020

There was a large display of NLC this morning from my location just South of London. I first saw it at at 02:07 UTC (Solar elevation - 10.13 degrees) and was still in progress at 02:46 UTC (Solar Elevation -6.78 degrees) when it was wiped out by dawn. It appeared to stretch for at least the NE to NW...